Feature
1) Built-in bias resistors enable the
   configuration of an inverter circuit
   without connecting external input
   resistors (see equivalent circuit).
2) The bias resistors consist of thin
   film resistors with complete isolation to
   allow positive biasing of the
   input. They also have the advantage of
   almost completely eliminating parasitic effects.
3) Only the on / off conditions need to
   be set for operation, making device
   design easy.